We all know that, sadly, lightsabers will probably never be a reality, there's no sound in space, and that objectively, spaceships probably wouldn't fall downward when hit in a space firefight (because of that whole no gravity thing). But now, a group of astronomers from UC Berkeley are here to tell us about all of the other things that Star Wars gets wrong about space, including faster-than-light travel, spaceship fuel, and the density of asteroid fields.

First, although they're all Star Wars fans themselves, they concede that Star Wars's hyperdive is less realistic than Star Trek's warp drive. Faster-than-light travel is always hypothetical, but the hyperdrive's FTL travel depends entirely on the existence of hyperspace, an alternative region of space in which the rules of general relativity don't apply, which is hypothetical at best.

"It's interesting that they went the hyperspace route to me," Chelsea Axen told The Daily Dot. "At least warp drive kind of goes with general relativity; you're literally warping spacetime. Hyperdrive allows you to access hyperspace-that's a whole other dimension. In terms of the science, that's pretty hypothetical."

Another, more practical problem is fuel. While an object in motion will stay in motion while floating in space, that's only if they're going in the same direction. In order to change direction, you need propulsion, which requires the consumption of some sort of fuel. The spacefights in Star Wars, in which the ships are doing crazy maneuvers in all different directions, are technically possible, but they would take an astronomical amount of fuel. Axen also cited the scene in Empire Strikes Back in which Luke plans to go to Hoth, but changes course for Dagobah, without any concern for the amount of fuel he had on hand.

"Fueling space ships is one of the most difficult things about space ships," Axen said. "[Star Wars is] the land of infinite fuel."

And then there's another iconic scene in Empire Strikes Back that doesn't quite make the science grade: Han's threading through the Hoth asteroid belt. According to Andy Howell, the astrophysicist behind Science vs. Cinema, it is completely implausible that the asteroids would be close enough together relative to the size of a human spaceship to require any type of precise maneuvering. In real life, they would be so far apart, it would be "like trying to walk through an empty parking lot without getting hit by a car."

Technically, the asteroids could be that close together, but the humans who drive the spaceships wouldn't exist yet. When debris is that close together in space, that's an indication that planet formation is occurring, and therefore the creatures who fought in the Star Wars wouldn't have evolved yet.

But while Star Wars may be more fantasy than hard science fiction, there are a few things it gets right. Tatooine, for example, is completely realistic, as we have discovered several real-life analogues of planets with two suns.

"We've now found a few cases where there are circumbinary planets. Those are planets around a double-star system," said Howell. "There are a lot of different configurations you can have, but one is you can find two stars and then you can have planets orbiting around that."

And the TIE fighters, while not completely realistic, are somewhat based in truth. It is established that they use ion engines, which NASA actually uses in their spaceships today.

"You basically ionize gas, and then you use it to accelerate particles out of the back of some engine to create thrust," said Howell. "If you told the 4-year-old me [seeing Star Wars for the first time] that when I was an adult we'd have some of this stuff. I'd be floored."

But overall, Star Wars is not necessarily attempting to be an accurate representation of space, but rather use space in order to tell an emotionally accurate story.

"So, Star Wars is going for more of an emotional truth. They want things to just sort of feel right and move you in a certain way. Scientific accuracy is not at the top of the list of things it wants to achieve," Howell said.